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Area Forecast Discussion (AFD)

Issued by San Diego, CA (SGX)

                            
000
FXUS66 KSGX 181054
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
354 AM PDT Thu Jul 18 2019

.SYNOPSIS...
A weak trough of low pressure near the California coast will 
continue the slow cooling trend and slow deepening trend of the 
marine layer into Friday with not much change for Saturday. Areas
of night and morning low clouds will spread into portions of the
inland values and may be slow to clear in the afternoon for some
coastal areas. For Sunday through Wednesday, strengthening high 
pressure to the east will bring an influx of monsoonal moisture 
with increasing humidity for inland areas. Chances for 
thunderstorms, mainly near the mountains during the afternoons and
early evenings, will begin around Monday. The marine layer will 
become shallower for Sunday through the middle of next week with
night and morning coastal low clouds patchier and not spreading as
far inland.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

.SHORT TERM (Today through Saturday)...
The weak trough of low pressure near portions of the California
coast will continue the slow cooling trend and slow deepening of 
the marine layer into Friday with not much change for Saturday. 
Areas of night and morning coastal low clouds will spread into 
portions of the inland valleys. Afternoon clearing may continue to
be slow near some portions of the coast. 

&&

.LONG TERM (Sunday through Wednesday)...
High pressure centered over Colorado and Utah will strengthen and
expand into the southwest states. This will bring an influx of
monsoonal moisture beginning Sunday and continuing through the
middle of next week. Chances for thunderstorms, with greater
chances near the mountains during the afternoons, will begin
around Monday. There remain differences among the global models
and their ensemble members with the placement and orientation of
the high pressure, which will impact the details of the moisture
influx and resulting thunderstorms chances. 

The marine layer will become shallower with night and morning
coastal low clouds becoming patchier and not extending as far
inland. High temperatures in the valleys will warm as the marine 
layer becomes shallower. Nights will generally be warmer. High 
temperatures elsewhere for inland areas will be modulated by the 
monsoonal moisture and cloud cover, but will generally be not 
quite as hot. 

&&

.AVIATION... 
180900Z...Coast/Valleys...Marine stratus from the coastal waters to 
around 25SM inland with bases 800-1200 FT MSL and tops near 2000 FT 
MSL. Along the higher coastal terrain and along the inland extent of 
the stratus deck...areas of VIS 3-5SM BR and locally below 3SM BR/FG 
through 14Z. Stratus deck will mix out from the valleys toward the 
coast 15Z-19Z, with only partial clearing along the immediate coast 
and offshore. BKN-OVC stratus may start pushing back inland 02Z-04Z 
with bases 1000-1400 FT MSL. 

Mountains/Deserts...Clear with unrestricted VIS through tonight. 
Areas of west winds 20-25KTG35KT through and below passes and near 
the desert slopes late this afternoon through tonight.  

&&

.MARINE... 
No hazardous marine weather expected through Tuesday.

&&

.SKYWARN... 
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...17
AVIATION/MARINE...JAD